Adding a photo directly to iPhone disk

I tried to add a picture in the folder /User/Media/DCIM/100APPLE/ (the same as /private/var/mobile/DCIM/100APPLE/), but it doesn't show up in the Camera Roll.

How can we make it appear?
It's an iPhone 3G running iOS 4.3.1.

Solution 1:

Following the advice in this forum thread, I've deleted the files (after backing up to the computer):

• /User/Media/PhotoData/com.apple.photos.caches_metadata.plist
• /User/Media/PhotoData/Photos.sqlite
• /User/Media/PhotoData/PhotosAux.sqlite

After opening the Photos app again, it rebuilds the Library:

It's important to use the pattern IMG_0000.ext for the pictures file names:

• 0000 being numeric ID of our choosing
• .ext is a JPG or PNG extension
• we can add letters after the numeric ID to prevent conflicts with the device ID counter, ie, IMG_0041b.png, IMG_0041c.png, IMG_0041d.png.